From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793829585; b=qP8NuqkHafQzmFgxMfPsQilN7Wmrn9sFvNdT+wu5An7WZcZ2AHaOWvRGn5ap4JvLFklc /mwH7zR1pjVQQ8plADBbBDthsLf1doWJp4aWb0WisQEMO7RPDJgNFc2yNdnr6OFYjMGzy bFibi2sOfEWH+HMslZYjnqQQ15FIkf191OOpY/aSwdoBxvHr6V3PYOqNrlzNf50VQkaP8 wBJkdfpKQ9CdGTM/xNy7q5JpaTxVba4YKVV84gS2+EifVODqpPkfyFK8odz7BcOxPtIDv PnVdYYJXdR7uDeMaiiYUdrzgtVatO158JWoytXCwuNQ9SxHvi02C0MItS0GCfM+5iyw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793829585; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=71TulCmlbzNSmdj5nN/9bya2jiBZelc9dmC+CWXtgrY=; b=lf2Qxd2Ch84s35+i+GxB/xQXUXQKHSKpkzU7pZyktuuGsEKkQw+7t/Rjhmw4cSB5AfJa 0nIbqwwIj+wL5heIPq88KAxGM3743NAG5ByKCpaSaHXDBsS6M6IlFnb6TSIjS77O27vK6 maRuci1WW8/fXdoTx5Ihi02NA/HEsCT7RsPSna1mGh96hiojlrtSCUdCFOpICBifMqz4Y UK7k0ZkdZ4Or8X9DVB8Kp4IWBvhr9FjuLRbuH0X1AiQ0R1dF7GjMjNsifKJA01GfFXT7J sv9+ZQbhMadMA2LPk/RGnlKsxz4ildY4Dcboc+c3yp68RaDLRa/ei5zV7Iay6Sn0IAA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=MEVSJ38g; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 447AA606B399; Wed, 4 Nov 2026 21:59:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=MEVSJ38g Received: by smtp.kernel.org (Postfix) with ESMTPSA id C94681F00919; Wed, 4 Nov 2026 21:59:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793829585; bh=71TulCmlbzNSmdj5nN/9bya2jiBZelc9dmC+CWXtgrY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=MEVSJ38g+W89+BYDvTEdA23PNdSAMC9QL0YzAUmI4FnmO2GvhKKh4UlsypnPn3zRa zz4VI9m4Etazoky0V0GXmOQE42F2ZizO78PICVC4SFoG6ipy6idzoP6UUo0gMbQpyR AajzYBo+EnhhRn7xqM5ATTsm+FIKEJtLPK3Y8XPo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuan-Wei Chiu , Pu Lehui , Kumar Kartikeya Dwivedi , Sasha Levin Subject: [PATCH 6.18 0216/1005] riscv, bpf: Add support for BPF_SDIV and BPF_SMOD in RV32 JIT Date: Wed, 4 Nov 2026 15:59:09 -0500 Message-ID: <20261104211049.865121647@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kuan-Wei Chiu [ Upstream commit 2e0fa2389c50fd3a69bb738efa74e127b7516938 ] The current rv32 bpf jit compiler incorrectly treats BPF_SDIV and BPF_SMOD as unsigned operations. The BPF instruction set allows signed division and modulo by reusing the BPF_DIV and BPF_MOD opcodes with the instruction offset set to 1. Update the emit_alu_r32() function to accept an 'is_sdiv' variable and emit the correct div and rem instructions when the offset is 1. Before this patch: [ 44.161771] test_bpf: #165 ALU_SDIV_X: -6 / 2 = -3 jited:1 ret 2147483645 != -3 (0x7ffffffd != 0xfffffffd)FAIL (1 times) [ 44.167385] test_bpf: #166 ALU_SDIV_K: -6 / 2 = -3 jited:1 ret 2147483645 != -3 (0x7ffffffd != 0xfffffffd)FAIL (1 times) [ 44.171053] test_bpf: #169 ALU_SMOD_X: -7 % 2 = -1 jited:1 ret 1 != -1 (0x1 != 0xffffffff)FAIL (1 times) [ 44.172081] test_bpf: #170 ALU_SMOD_K: -7 % 2 = -1 jited:1 ret 1 != -1 (0x1 != 0xffffffff)FAIL (1 times) After this patch: [ 16.002192] test_bpf: #165 ALU_SDIV_X: -6 / 2 = -3 jited:1 95 PASS [ 16.002983] test_bpf: #166 ALU_SDIV_K: -6 / 2 = -3 jited:1 1059 PASS [ 16.017167] test_bpf: #169 ALU_SMOD_X: -7 % 2 = -1 jited:1 136 PASS [ 16.023002] test_bpf: #170 ALU_SMOD_K: -7 % 2 = -1 jited:1 109 PASS Signed-off-by: Kuan-Wei Chiu Reviewed-by: Pu Lehui Link: https://lore.kernel.org/bpf/20260714002451.4091139-2-visitorckw@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi Signed-off-by: Sasha Levin --- arch/riscv/net/bpf_jit_comp32.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/arch/riscv/net/bpf_jit_comp32.c b/arch/riscv/net/bpf_jit_comp32.c index 592dd86fbf811..89153946a4e46 100644 --- a/arch/riscv/net/bpf_jit_comp32.c +++ b/arch/riscv/net/bpf_jit_comp32.c @@ -509,12 +509,15 @@ static void emit_alu_r64(const s8 *dst, const s8 *src, } static void emit_alu_r32(const s8 *dst, const s8 *src, - struct rv_jit_context *ctx, const u8 op) + struct rv_jit_context *ctx, + const struct bpf_insn *insn) { const s8 *tmp1 = bpf2rv32[TMP_REG_1]; const s8 *tmp2 = bpf2rv32[TMP_REG_2]; const s8 *rd = bpf_get_reg32(dst, tmp1, ctx); const s8 *rs = bpf_get_reg32(src, tmp2, ctx); + u8 op = BPF_OP(insn->code); + bool is_signed = insn->off == 1; switch (op) { case BPF_MOV: @@ -539,10 +542,12 @@ static void emit_alu_r32(const s8 *dst, const s8 *src, emit(rv_mul(lo(rd), lo(rd), lo(rs)), ctx); break; case BPF_DIV: - emit(rv_divu(lo(rd), lo(rd), lo(rs)), ctx); + emit(is_signed ? rv_div(lo(rd), lo(rd), lo(rs)) : + rv_divu(lo(rd), lo(rd), lo(rs)), ctx); break; case BPF_MOD: - emit(rv_remu(lo(rd), lo(rd), lo(rs)), ctx); + emit(is_signed ? rv_rem(lo(rd), lo(rd), lo(rs)) : + rv_remu(lo(rd), lo(rd), lo(rs)), ctx); break; case BPF_LSH: emit(rv_sll(lo(rd), lo(rd), lo(rs)), ctx); @@ -1041,7 +1046,7 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx, emit_imm32(tmp2, imm, ctx); src = tmp2; } - emit_alu_r32(dst, src, ctx, BPF_OP(code)); + emit_alu_r32(dst, src, ctx, insn); break; case BPF_ALU | BPF_MOV | BPF_K: @@ -1065,7 +1070,7 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx, * src is ignored---choose tmp2 as a dummy register since it * is not on the stack. */ - emit_alu_r32(dst, tmp2, ctx, BPF_OP(code)); + emit_alu_r32(dst, tmp2, ctx, insn); break; case BPF_ALU | BPF_END | BPF_FROM_LE: -- 2.53.0